The overall aim of the project is to develop and extend the infrastructure already in place at the Agincourt Health and Population Unit (AHPU) at the University of the Witwatersrand (Wits) in Johannesburg, South Africa and at the University of Colorado ? Boulder (CU) to: 1) Improve infrastructure and build capacity for social science AIDS research at AHPU/Wits;2) Evaluate the introduction of ART in rural South Africa by using the Agincourt Health and Demographic Surveillance System (AHDSS) longitudinal data to examine socioeconomic differentials in uptake of and adherence to treatment and short-term effects of treatment, including impacts on affected individuals and their families (specifically elders);and 3) Study the socioeconomic effects of AIDS by conducting research projects on the measurement of and models for HIV prevalence and mortality;the socioeconomic impacts of AIDS on individual, family and community (including elderly);and evaluation of HIV intervention (prevention) programs, and how they change the socioeconomic impacts of AIDS. All studies will take advantage of and benefit from the ongoing records of the Agincourt Health and Demographic Surveillance System and the work of the Wits AHPU.